A stencil filler solution



2,731,356 7 A STENCIL- FILLER SOLUTION- Earl G. Conley, Tulsa, ok a.

No Drawing; Application December 18, 19 52, Serial No. 326,668 -f 4 Claims. (clams-um This invention relates to the art of stencil printing and,

surface ornamentation, and more particularly to the method and materials for preparing silk screens for use in printing designs by forcing inks, dye pastes and the like therethroug Sheets of waxed-paper or films of cellophane, lacquersand the like for preparing stencils for silk screen printing have been in commercial use for sometime, and in accordance with existing practices portionscorresponding to the design to be printed are removed from the sheet by the use of a suitable solvent or by manuallyicutting the design therefrom and the remaining sheet then caused to adhere to the screen by the use of a h0t iron or by means of a suitable solvent which renders the sheet tacky and capable of being adhesively secured to the screen.

In modern practice a film impervious to inksand the like to be used in the printing is mounted on a carrier and the design cut from the film. Once the film is cut the exposed surface thereof is placed in contact with fine silk fabric or other suitable material and a solvent apthrough the fabric, the;

plied to the surface of the film solvent rendering the surface of the film tacky or adhesive and causing the entire film to adhere to the Qsilk screen. The stencil film is usually mounted on the carrier sheet with a release compound or adhesive'so that when. the stencil film is adhered to the silk screen the carrier sheet is peeled away from the adhered stencil film. The fine silk fabric is, of course, mounted upon a suitable frame under sufiicient tension to maintain the fabric smooth. In using such stencils the object to be printed is placed under the silk screen and inks or the like arranged in a reservoir area at one end of the frame are pulled across the film with a squeegee, forcing the ink through the cutout portions of the'film and through the silk screen onto 'the object to apply the' design thereto. iln many'itlstances the film does not cover the-entire silk screen, or l there; may bea portion of the design whichis not desired to be reproduced.- In such instances it is commonpra'ctice to use a stencil filler made from a lacquer base'or t'lle like and apply same with a brush to the areas of the silk screen which are desired to be ink impervious. Lacquer and acetate type fillers require expensive, explosively inflammable solvents and clean up thinners. Water-soluble stencil fillers have been used but such fillers use water in their formulation causing relatively slow drying. They also exhibit extreme expansion and contraction under conditions of excessive humidity.

The objects of the present invention are to provide a solvent adhering type, knife-cut stencil which is watersoluble and may be removed from the silk mesh after use by noninflammable materials such as water; to provide a solvent adhering type knife-cut stencil composed principally of water-soluble cellulose ether such as methylcellulose and a suitable plasticizer and coloring pigment, the film being mounted on a transparent backing sheet 'th a release compound whereby the backing sheet is ge movable from the film after the film is cut and adhered ents and cleaners commonly used to a silk screen mesh; to provide a silk stencil filler of water-soluble cellulose ether and volatile organic solvents which can be spread over the surface of silk screen stencils and quickly dried to form a cellulose film; to provide such a stencil filler that although originally deposited from an organic solvent may be easily removed with' Water; to provide 'such a stencil filler of principally methylcellulose and volatile organic solvents wherein the Y filler is fast-drying, the solvents are not explosively inflammable and when applied and dried the cellulose film is impervious to solvent action of all organic plaint diluin the silk screen industry but is soluble in water eliminating the use'of ex pensive, thinners.

In accordance with the present invention the stencil is composed of a cellulose ether which is watersoluble, for example methyl-cellulose, and'a plasticizer, such as sulfonated castor oil lose ether and plasticizer to final film to aid in the detection of pinholes. The following examples of the film composition:

The compositions, Examples I or-II, or methyl-cellulose alone, are dissolved in water or a suitable organic solvent such as formamide, tetrachloroethane, bromoform, benzyl alcohol, ethylene chlorohydrin, ethyl glycollate, methyl salicylate, aniline, pyridine, quinoline or chloraniline.

The solution may be applied by means of a coating machine, spraying or'any other desired method to a carrier sheet to form a film. Two or more coats of the solution may be used to obtain a relatively thicker film. The film is then suitably dried by passing it through a drying oven or otherwise.

The carrier sheet is preferably cellophane, glassine paper or other transparent material which, before coating with the cellulose ether solution, had previously been coated with a release compound'in the form of a rubber cement or other suitable material that will hold the cellulose ether film to the carrier sheet whereby the carrier sheet will serve as a backing sheet and permit the sheet to be peeled from the film after the film is, adhered toa silk screen. The cellulose ether film also may be 'suitably formed'and then such film applied to a backing sheet coated with a suitable release compound or adhesive to hold the film on said backing sheet during cutting and application to a silk screen. The film and transparent backing sheet are relatively transparent when placed in contact with artwork or other designs which the operator may wish to reproduce. The patterns, letters or designs are cut through the cellulose film to the backing sheet by means of a sharp blade. Areas which are to be printed on the final stencil are lifted away from the backing sheet and discarded. When the design has been cut on the film a silk fabric which is stretched on a stencil frame is placed in close contact with the film and an adhering solution applied to the silk fabric by means of a solvent dampened cloth, the solvent penetrating the silk fabric causing the surface of the film contacting the silk fabric to become tacky and due to the pressure holding the film in contact with the silk fabric the film is adhered to the fabric when the adhering solution has dried.

Patented l an. 17, 1956 explosively inflammable solvents and clean up or triethanolamine, and suit able pigmentation may be added to the mixture of celluprovide desired color in the The stencil frame is then lifted and the transparent backing paper is peeled away from the adhered stencil.

In further preparing the silk screen for use, the sill; fabric. aroundathe marginsmf :the =stencill-filnnoitrbetween t:

'the.= stencil film, anditthet-silkv screen framejrare :rendered-i:

hydrin, fl1yl-,', glycollatetc. methyl-"1. salicylate,=;.v aniline; pyridine ,quinoline,.--ichloranilinewor a mixture :of-methvla ene chloride, ethylene-dichlorideandcarbon tetrachloride Methylene. chloride,.-. ethylene;dichlorideteandm carbon tetrachloride are not individually solvents of methyl-,eellu-: loseibut. are: .cosolven-ts When/used; inicombiuationeavith The:water solubleacelluw 10 methyl. .alcoho1..-: There. are aother organic. solvents ofz methyl cellulose:whichxould-be-used, however, it'is ,pre erablepto.utilizethe mostwolatilesolvents"totobtainsrnax mum;-rapidity:;of'.=drying, Any. ,suitableplasticizerszfo methyl-cellulose.may,-betused,. however; :best results thavew-r beenobtained'bypsesof-either sultonated castor oil .or.-tri1.--

ethanolamine. An example-ota suitable-mixture; t -the. materials to form stencil filler is eight (8) ounces of methyl-cellulose, one (1) gallon =of solvent and two (2) ouncesof plasticizer and pigment if desired for coloring same.

hr the above examples, specific proportionsrare mena tioned but while these proportions are very suitable, I do not restrict the present inventi'onto these proportions. The -stencil filler solution when applied by a squeegeeiori brush onto the open silk mesh dries in threetofivemin-k: utes in a tough, continuous film which fills the open mesh of the silk, thus producin'g a surface which is impervious to the 'actionof --'paints;- dye pastes and- 'inlcs comm-only" used insilk' screen -process printing and their L solvents This fil'm' GXhlbitSLVCI'YiSll-ghi' change' -in dimensionab sta=- bility": upon:- exposure to :varying conditions ofhumidity; The stencil filler solution may also beused to' sprayor otherwise coat a backing sheet toform'a knife cutsolvent adhering stencil filmr The filmwhen dry, although origi nally' 'deposited from an organic: solvent," may be easily removedwithr tapavvater: Also the non-inflammable sol vent or water may he used for clean up on the stenciland F afterlusefof thestencil the stencil and the filler may be removed withllordin'ary" tap water.

lt is believed obvious'thatI have provided a solvent adhering, :waten-soluble, knife cut -stencil film and- 'water'-- solublelstencilfillr"which reduce necessary time of pre-=' paring.silkxscreens fot use and 'also reduce the hazardsconnectedi'itherewithl as well as simplifying tthe removalof the stencil and-'filler from-the silk screen:

What :I claim. and 'desire tosecure byletters Patent is l. A stencil filler solution consisting of inethyl-cellu lose, a solvent consisting of a mixture of. methylene. chlo; ride, ethylene dichloride, carbon tetrachloride and methyl alcohol, and triethanolamine, said solution being characterized by its being not explosively inflammable and its rapid drying when applied to a foraminous painting screen to form a film which is water soluble and is impervious to the solvent action of organic diluents and cleaners used in silk screen processes.

2. A composition t whi'ch is not explosively inflammable and which when spread on-a surface .quickly dries in a cellulose film coating that 'is" water soluble and is substantially; imperviouszjtoz thett solvent ractionr of organic paint diluents and cleanersused"insilkscreen processes,

consisting of methyl-'cellulose,-.a solventconsisting of a mixture of methylene chloride, ethylene dichloride, carbon tetrachloride and methyl alcohol, and a plasticizer.

3. A composition which is not explosively inflammable and which when spread on a surface quickly dries in a cellulose-zfilmecoatingathat is'water soluble and is'substantially imperviouwto- 'the solvent action of organic paint di1uents; .and 'cleaners used-in silE screen processes, con-" sisting 1 0f" nnixmr ez of s ittt 'parts"methyl-cellulosaand 20 a solvent -consisting of a-- parts sulfonated castor oil, and mixture of methylene chloride, ethylene dichloride; --carhon tetrachlorideancl'inethyl alcohol.-

43 Atcompositi'on' which' is notexpldsively inflammable and- -"-which-'-wvhen spread;on a surface quickly dries in-a cellnlose filn'r coating sthat is -water= soluble and is sub- 1 stantiallyimpervious'to the solvent action of organic paint diluents and cleanerszused in" silk screen processes, con-' sistingxof a' rnixture ot parts smethyl-cellulose and 20 parts triethanolaminepand a: solvent consistingof a mixture' oi metltylene chlorideg ethylene :dichloride; carbon tetrachlorideand htethyl alcohol;

RefrenceszCited initheifilemf this-patent- UNITED. STATES "PATENTS OTHER; REFERENCES.

land, Michigan;-*1948 pages 12;15, l6and18i' Simonds eetaalsi Handbook of *Plastics,'. 2nd edition;-

l949,'-ID Van=Nostrand Co2', Inc"; New York-. Only-page 399 *"citedi i 

1. A STENCIL FILLER SOLUTION CONSISTING OF METHYL-CELLULOSE, A SOLVENT CONSISTING OF A MIXTURE OF METHYLENE CHLORIDE, ETHYLENE DICHLORIDE, CARBON TETRACHLORIDE AND METHYL ALCOHOL, AND TRIETHANOLAMINE, SAID SOLUTION BEING CHARACTERIZED BY ITS BEING NOT EXPLOSIVELY INFLAMMABLE AND ITS RAPID DRYING WHEN APPLIED TO A FORMINOUS PAINTING SCREEN TO FORM A FILM WHICH IS WATER SOLUBLE AND IS IMPREVIOUS TO THE SOLVENT ACTION OF ORGANIC DILUENTS AND CLEANERS USED IN SILK SCREEN PROCESSES. 